This publication presents the proceedings of an IAEA technical meeting, Quality Control Procedures for Nuclear Instruments. The importance of tests for continued quality assurance (QA) and quality control (QC) in the maintenance of nuclear instruments is paramount in ensuring their precision, reliability and longevity. This publication provides examples of the range of available testing methods, as illustrated by fieldwork case studies in the areas of environmental monitoring, industry, human health and nuclear research. The publication’s focus reflects the needs of Member States in the field of QA/QC procedures. Also included are future trends, validation procedures, educational training and tests and their test instructions.